Variable thickness preform for a bottle

ABSTRACT

A preform for a container has a hollow cylindrical main body having a first thickness, a hollow cylindrical thick portion having a second thickness greater than the first thickness, and a curved end portion. Inner surfaces of the main body, the thick portion, and the end portion form a cavity.

BACKGROUND Field of the Disclosure

The present invention relates to a preform for forming a container. Morespecifically, the present invention relates to a preform for forming acontainer with a variable thickness.

Description of the Related Art

Conventionally, numerous types of containers, including plastic bottlesfor holding fluids, are formed by blow molding. For some applications,handles are desired for carrying the container.

The handles are usually attached in a separate process step, after themain body of the container was formed by blow molding. For example,after removal of the formed container main body from the blow mold, theformed container main body may then be transferred to another mold andthe handle may be formed onto the formed container main body byinjection molding. Alternatively, a separately formed handle may besnapped onto the neck of the formed container main body.

Other examples of methods for forming a container with a handle are setforth in the background section of U.S. Pat. No. 8,524,143. U.S. Pat.No. 8,524,143 and U.S. Pat. No. 9,505,163, which disclose a method forforming a container with an integral handle and a container with anintegral handle notch, are hereby incorporated by reference in theirentirety.

Additionally, preforms for forming plastic bottles conventionally have auniform thickness, such that the preform can be easily removed from apreform mold.

SUMMARY

According to one or more embodiments of the present invention, a preformfor a container comprises a hollow cylindrical main body having a firstthickness, a hollow cylindrical thick portion having a second thicknessgreater than the first thickness, and a curved end portion, whereininner surfaces of the main body, the thick portion, and the end portionform a cavity.

According to one or more embodiments of the present invention, an outerdiameter of the thick portion is greater than that of the main portion.

According to one or more embodiments of the present invention, an innerdiameter of the thick portion is the same as that of the main portion.

According to one or more embodiments of the present invention, a preformfor a container comprises a tapered transition portion formed betweenthe main body and the thick portion, such that the thickness increasesgradually from the main body to the thick portion.

According to one or more embodiments of the present invention, a preformfor a container comprises a threaded neck portion disposed above themain body.

According to one or more embodiments of the present invention, a preformfor a container comprises an integral handle attached to the main bodyat an upper attachment point, and attached to the thick portion at alower attachment point.

According to one or more embodiments of the present invention, a preformfor a container comprises an integral handle attached to the main bodyat both an upper attachment point and a lower attachment point.

According to one or more embodiments of the present invention, a preformfor a container comprises an integral handle attached to the main bodyat an upper attachment point, and attached to the tapered transitionportion at a lower attachment point.

According to one or more embodiments of the present invention, the mainbody comprises a tapered inner diameter transition portion thatgradually decreases an inner diameter of the main body in the downwarddirection.

According to one or more embodiments of the present invention, a preformfor a container comprises an upper handle attachment notch disposed onthe main body, and a lower handle attachment notch disposed on thetapered transition portion.

According to one or more embodiments of the present invention, a preformfor a container comprises another thick portion disposed on an upperside of the main body and having a third thickness greater than thefirst thickness, wherein the thick portion is disposed on a lower sideof the main body.

According to one or more embodiments of the present invention, a moldfor forming a preform comprises a first preform mold comprising a firstpreform mold cavity that includes a first top opening and a first bottomopening, a second preform mold comprising a second preform mold cavitythat includes a second top opening and a second bottom opening, a thirdpreform mold comprising a third preform mold cavity that includes athird top opening, and a third bottom opening, and a rod-shaped innermold. The first preform mold and the second preform mold are configuredto be combined such that the first and second preform mold cavities forma first space corresponding to an outer shape of an upper portion of thepreform having a variable outer diameter. The third preform mold cavityhas a second space corresponding to an outer shape of a lower portion ofthe preform having a constant outer diameter. The rod-shaped inner moldis configured to be inserted into the first, second, and third preformmold cavities, and corresponds to an inner cavity of the preform. Thethird preform mold is structured such that molten plastic can beinjected through the third bottom opening.

According to one or more embodiments of the present invention, when thefirst, second, and third preform molds are combined, the first andsecond bottom openings of the first and second preform mold cavitiescommunicate with the third top opening of the third preform mold cavity,such that molten plastic injected from the third bottom opening can flowto the first and second preform mold cavities.

According to one or more embodiments of the present invention, the firstand second mold cavities comprise recesses in the shape of a handle.

According to one or more embodiments of the present invention, a methodfor forming a preform comprises closing a first preform mold comprisinga first preform mold cavity that includes a first top opening and afirst bottom opening, a second preform mold comprising a second preformmold cavity that includes a second top opening and a second bottomopening, such that the first and second preform mold cavities form afirst space corresponding to an outer shape of an upper portion of thepreform having a variable outer diameter, disposing a third preform moldcomprising a third preform mold cavity that includes a third topopening, and a third bottom opening below the closed first and secondpreform molds, the third preform mold cavity having a second spacecorresponding to an outer shape of a lower portion of the preform havinga constant outer diameter, inserting a rod-shaped inner mold into thefirst, second, and third preform mold cavities, injecting molten plasticthrough the third bottom opening into the first, second, and thirdpreform mold cavities, and around an outside of the rod-shaped innermold, cooling the molten plastic to form a hardened plastic preform,removing the first, second, and third preform molds to expose an outsideof the preform, and removing the rod-shaped inner mold from the preform.

According to one or more embodiments of the present invention, the firstand second mold cavities comprise recesses in the shape of a handle.

According to one or more embodiments of the present invention, at leasta portion of the inner diameter of the closed first and second preformmold cavities is greater than an inner diameter of the third preformmold cavity.

BRIEF DESCRIPTION OF DRAWINGS

Features of the present disclosure will become more apparent from thefollowing description in conjunction with the accompanying drawings.

FIGS. 1 A and 1B show inside views of a first preform mold and a secondpreform mold for forming a preform according to one or more embodimentsof the present invention.

FIG. 1C shows a front view of a bottom preform mold for forming apreform according to one or more embodiments of the present invention.

FIG. 1D shows a front view of a rod-shaped inner mold for forming apreform according to one or more embodiments of the present invention.

FIGS. 2A-2D show a manufacturing process for forming a preform accordingto one or more embodiments of the present invention.

FIGS. 3A-3C show a preform stretching apparatus and a preform stretchingprocess with the preform removed according to one or more embodiments ofthe present invention.

FIGS. 3D-3F show a preform stretching apparatus and a preform stretchingprocess according to one or more embodiments of the present invention.

FIGS. 4A-4B show inside views of a first blow mold and a second blowmold according to one or more embodiments of the present invention.

FIGS. 5A-5B show a manufacturing process for forming a container from astretched preform according to one or more embodiments of the presentinvention.

FIG. 6 shows a cross-sectional view of a preform according to one ormore embodiments of the present invention.

FIGS. 7A-7C show front views of a preform, a stretched preform, andblown container, according to one or more embodiments of the presentinvention.

FIG. 8 shows a cross-sectional view of a preform according to one ormore embodiments of the present invention.

FIGS. 9A-9C show front views of a preform, a stretched preform, andblown container, according to one or more embodiments of the presentinvention.

FIG. 10 shows a cross-sectional view of a preform according to one ormore embodiments of the present invention.

FIGS. 11A-11C show front views of a preform, a stretched preform, andblown container, according to one or more embodiments of the presentinvention.

FIG. 12 shows a cross-sectional view of a preform according to one ormore embodiments of the present invention.

FIGS. 13A-13C show front views of a preform, a stretched preform, andblown container, according to one or more embodiments of the presentinvention.

FIG. 14 shows a cross-sectional view of a preform according to one ormore embodiments of the present invention.

FIGS. 15A-15B show cross-sectional views of a preform and a stretchedpreform, and FIG. 15C shows a front view of a blown container, accordingto one or more embodiments of the present invention.

FIG. 16 shows a cross-sectional view of a preform according to one ormore embodiments of the present invention.

FIGS. 17A-17B show cross-sectional views of a preform and a stretchedpreform, and FIG. 17C shows a front view of a blown container, accordingto one or more embodiments of the present invention.

DETAILED DESCRIPTION

Embodiments of the invention will be described in detail below withreference to drawings. In embodiments of the invention, numerousspecific details are set forth in order to provide a more thoroughunderstanding of the invention. However, it will be apparent to one ofordinary skill in the art that the invention may be practiced withoutthese specific details. In other instances, well-known features have notbeen described in detail to avoid obscuring the invention.

FIG. 1A shows an inside view of a first preform mold 810 according toone or more embodiments of the present invention. The first preform mold810 has a first preform mold cavity 811 formed therein. The firstpreform mold cavity 811 extends to the top and bottom of the firstpreform mold 810, so that the first preform mold 810 has top opening 813and a bottom opening 815. Here, the diameter of the bottom opening 815is equal to a maximum diameter of the bottommost portion of the preform.

FIG. 1B shows an inside view of a second preform mold 820 according toone or more embodiments of the present invention. The second preformmold 820 has a second preform mold cavity 821 formed therein. The secondpreform mold cavity 821 extends to the top and bottom of the secondpreform mold 820, so that the second preform mold 820 has a top opening823 and a bottom opening 825. Here, the diameter of the bottom opening825 is equal to a maximum diameter of the bottommost portion of thepreform. According to one or more embodiments of the present invention,the second preform mold cavity 821 is a mirror image of the firstpreform mold cavity 811. Alternatively, the second preform mold cavity821 may have a different shape from a mirror image of the first preformmold cavity 811.

FIG. 1C shows a front view of a bottom preform mold 830 for forming apreform according to one or more embodiments of the present invention.The bottom preform mold 830 has a third preform mold cavity 831 formedtherein. The third preform mold cavity 831 extends to the top of thebottom preform mold 830 to form a top opening 833. The bottom of thethird preform mold cavity 831 is within the bottom preform mold 830,with a thin bottom opening 835 through which molten thermoplastic can beinjected. The diameter of the top opening 833 of the bottom preform mold830 is equal to the diameter of the bottom openings 815, 825 of thefirst and second preform molds 810, 820.

FIG. 1D shows a front view of a rod-shaped inner mold 850 for forming apreform according to one or more embodiments of the present invention.Here, the rod-shaped inner mold 850 has a constant diameter down to theleading edge portion 851 thereof Alternatively, the rod-shaped innermold 850 may have variable diameters, as long as the diameter does notincrease in the downward direction, because such a shape may prevent therod-shaped inner mold 850 from being removed from the preform.

FIGS. 2A-2D show a manufacturing process for forming a preform accordingto one or more embodiments of the present invention. As shown in FIG.2A, the first and second preform molds 810, 820 are brought together inthe closed potion above the bottom preform mold 830 so that the topopening 833 of the third preform mold cavity 831 lines up with thebottom openings 815, 825 of the first and second preform mold cavities811, 821. The rod-shaped inner mold 850 is inserted into the closedfirst and second preform mold cavities 811, 821 and the third preformmold cavity 831 through the top openings 813, 823, 833 thereof. Moltenthermoplastic 840 is then injected into the third preform cavity 831through the thin bottom opening 835 thereof, so as to fill the spaceinside the third preform mold cavity 831 and up to top of the first andsecond preform mold cavities 811, 821, except for the space occupied bythe rod-shaped inner mold 850. The molten plastic 840 is then allowed tocool. According to one or more embodiments of the present invention, themolten plastic 840 is actively cooled by a cooling mechanism. Accordingto one or more embodiments of the present invention, the coolingmechanism may be one or more of a fan, an air conditioner, and a heatsink.

As shown in FIG. 2B, once the molten plastic 840 is cooled and hardened,the bottom preform mold 830 is removed by sliding downward off of thehardened preform 110, exposing the bottom portion of the preform 110.Subsequently, as shown in FIG. 2C, the first and second preform molds810, 820 are removed by moving in opposite directions away from thepreform 110. Finally, as shown in FIG. 2D, the preform 110 is sliddownward off of the rod-shaped inner mold 850 or, alternatively, therod-shaped inner mold 850 is removed by sliding upward from the preform110. Thereby, the preform 110 is formed. While the preform 110 shown inFIG. 6 is used as an example in FIGS. 1A-2D, a similar manufacturingprocess may be employed to form the preforms 210, 310, 410, 510, 610shown in FIGS. 8, 10, 12, 14, and 16, as well as other preforms.

FIGS. 3A-3C show a preform stretching apparatus 950 and a preformstretching process with the preform removed, according to one or moreembodiments of the present invention. The preform stretching apparatus950 has a base 959 on which a mandrel 953 and a first catching mechanism955 and a second catching mechanism 957 are disposed. A stretch rod 951extends upwards from an opening in the base 959 and the mandrel 953. Thestretch rod 951 has a leading edge 952 at a topmost portion thereof. Asshown in FIG. 3A, the first and second catching mechanisms 955, 957 areinitially distanced apart in the lateral direction. As shown in FIG. 3B,the first and second catching mechanisms 955, 957 are actuated to bebrought together around the mandrel 953. According to one or moreembodiments of the present invention, the actuator for actuating thefirst and second catching mechanisms 955, 957 are disposed within thebase 959. Thereafter, as shown in FIG. 3C, the stretch rod 951 extendsvertically upwards from the mandrel 953 and the base 959 to its finalposition.

FIGS. 3D-3F show a preform stretching apparatus 950 and a preformstretching process according to one or more embodiments of the presentinvention. As shown in FIG. 3D, a preform 110 is placed upside downaround the mandrel 953 and the stretch rod 951. As shown in FIG. 3E, thefirst catching mechanism 955 and the second catching mechanism 957 areactuated to be brought together around a neck portion 111 of the preform110, to secure the neck portion 111 therebetween. Thereafter, as shownin FIG. 3F, the stretch rod 951 extends vertically upwards from themandrel 953 and the base 959 to push on a base 121 of the preform 110,stretching at least the thick portion 117 and a tapered transitionportion 115 of the preform 110 until the stretch rod 951 reaches itsfinal position. After the stretch rod 951 reaches its final position, asshown in FIG. 3F, the stretched preform 130 is formed with an upperthinned portion 131 and a lower thinned portion 133 at positionscorresponding to the transition portion 115 and the thick portion 117,respectively.

According to one or more embodiments of the present invention, thepreform 110 is heated prior to being stretched by the stretch rod 951.According to one or more embodiments of the present invention, thepreform 110 is heated while being stretched by the stretch rod 951. Forexample, U.S. Pat. No. 9,505,163, which is incorporated by reference inthe present application, shows examples of heating of a preform prior tostretching with a stretch rod. According to one or more embodiments ofthe present invention, only the thick portion 117 of the preform 110and/or the tapered transition portion 115 is heated prior to and/orduring stretching by the stretch rod 951. According to one or moreembodiments of the present invention, in the orientation shown in FIGS.3D-3F, only a portion at and/or above a lower attachment point 127 isheated prior to and/or during stretching by the stretch rod 951.

By heating only the thick portion 117 of the preform 110 and/or thetapered transition portion 115, or by heating only a portion at and/orabove a lower attachment point 127, the shape of the integral handle 123may be maintained, without requiring shielding to be placed on theintegral handle 123. That is, no warping or unintended stretching of thehandle occurs from the heating and/or stretching process. According toone or more embodiments of the present invention, in the orientationshown in FIGS. 3D-3F, only a portion at and/or above a lower attachmentpoint 127 is heated prior to and/or during stretching by the stretch rod951.

While the preform 110 and stretched preform 130 shown in FIGS. 7A-7B areused as an example in FIGS. 3D-3F, a similar manufacturing process maybe employed to stretch the preforms 210, 310, 410, 510, 610 shown inFIGS. 9A, 11A, 13A, 15A, and 17A to form the stretched preforms 230,330, 430, 530, 630 shown in FIGS. 9B, 11B, 13B, 15B, and 17B, as well asother preforms. Furthermore, while first and second catching mechanisms955, 957 that are actuated together to secure the neck portion 111 isshown in FIGS. 3D-3F, other catching mechanisms may be employed as well.For example, U.S. Pat. No. 9,505,163, which is incorporated by referencein the present application, shows examples of catching mechanisms.Additionally, other catching mechanisms that are within a skill of aperson of ordinary skill in the art may be employed.

FIG. 4A shows an inside view of a first blow mold 910 according to oneor more embodiments of the present invention, and FIG. 4B shows a secondblow mold 920 according to one or more embodiments of the presentinvention. According to one or more embodiments of the presentinvention, each of the first blow mold 910 and the second blow mold 920is half of a complete mold, such that when the first blow mold 910 andthe second blow mold 920 are brought together, a complete mold isformed. A first mold catch 917 is disposed at the bottom of the firstblow mold 910, and a second mold catch 927 is disposed at the bottom ofthe second blow mold 920. As shown in FIG. 4A, the first blow mold 910has a first blow mold recess 911 in the shape of one side of the desiredcontainer, a lower handle recess 915, and an upper handle pocket wedgeblock 913. As shown in FIG. 4B, the second blow mold 920 has a secondblow mold recess 921 in the shape of the other side of the desiredcontainer, an upper handle recess 923, and a lower handle pocket wedgeblock 925. Examples of the upper handle pocket wedge block 913 and thelower handle pocket wedge block 925 are described in U.S. Pat. No.9,505,163, which is incorporated by reference in the presentapplication. The first mold catch 917 includes a semicircular first moldcatching surface 919, and the second mold catch 927 includes asemicircular second mold catching surface 929.

FIGS. 5A-5B show a manufacturing process for forming a container 150shown in FIG. 7C from a stretched preform 130 according to one or moreembodiments of the present invention. The first blow mold 910 and thesecond blow mold 920 are initially in the open position shown in FIG.5A. Once the stretched preform 130 disposed on the mandrel 950 ispositioned between the first blow mold 910 and the second blow mold 920,the first blow mold 910 and the second blow mold 920 are broughttogether to the closed position shown in FIG. 5B. As the first blow mold910 and the second blow mold 920 are brought together, the first moldcatching surface 919 of the first mold catch 917 and the second moldcatching surface 929 of the second mold catch 927 are brought togetheraround the neck portion 111 of the stretched preform 130, and the neckportion 111 of the stretched preform 130 is secured by the first andsecond mold catches 917, 927. Structures and operations of mold catchesare described in U.S. Pat. No. 9,505,163, which is incorporated byreference in the present application.

As the first and second blow molds 910, 920 are brought together, theupper handle pocket wedge block 913 that protrudes from the first blowmold 910 is inserted into an upper part of the handle pocket 124 of thestretched preform 130, and into the upper handle recess 923 of thesecond blow mold 920. Similarly, as the first and second blow molds 910,920 are brought together, the lower handle pocket wedge block 925 thatprotrudes from the second blow mold 920 is inserted into a lower part ofthe handle pocket 124 of the stretched preform 130, and into the lowerhandle recess 915 of the first mold 910. The tapered cam surface of theupper handle pocket wedge block 913 and the tapered cam surface of thelower handle pocket wedge block 925 function as cams on the integralhandle 123, pushing the integral handle 123 into an expanded position.According to one or more embodiments of the present invention, the upperhandle pocket wedge block 913 and the lower handle pocket wedge block925 merely moves the integral handle 123 into its final position on theblown container 150. Alternatively, the upper handle pocket wedge block913 and the lower handle pocket wedge block 925 may change the shape ofthe integral handle 123 while moving the integral handle 123 into itsfinal position on the blown container 150, such that the shape of theintegral handle 123 is modified. According to one or more embodiments ofthe present invention, the stretched preform is heated prior to beingplaced between the first and second blow molds 910, 920. According toone or more embodiments of the present invention, the stretched preformis heated while placed between the first and second blow molds 910, 920.

Once the first and second blow molds 910, 920 are in the closed positionshown in FIG. 5B, air is blown into the stretched preform 130 through amouth portion 112 thereof to form the blown container 150.Alternatively, according to one or more embodiments of the presentinvention, the blowing of the air into the stretched preform 130 startswhile the first and second blow molds 910, 920 are moving to the closedposition, so that the movement of the integral handle 123 of thestretched preform 130 to the expanded position occurs concurrently withexpansion of the stretched preform 130 during the blowing process. Oncethe blowing process is complete, and the stretch preform 130 hasexpanded to fill the first blow mold recess 911 and the second blow moldrecess 921 to form the blown container 150, and the blown container 150is sufficiently cooled, the first and second blow molds 910, 920 aremoved apart to an open position so that the blown container 150 may beremoved. According to one or more embodiments of the present invention,heated air may be blown into the stretched preform 130.

Although embodiments are described above in which the stretched preform130 is placed in the first and second blow molds 910, 920 in the openposition, the invention is not limited thereto. In one or moreembodiments of the present invention, the first and second blow molds910, 920 may be brought together around a non-stretched preform 110,securing the neck portion 111 of the preform 110 in the first and secondmold catching surfaces 919, 929. The stretch rod 950 may then beextended upwards to stretch the preform 110 within the closed first andsecond blow molds 910, 920 to form the stretched preform 130. However,to do so, the upper and lower handle pocket wedge blocks 913, 925 may berequired to be inserted into the first and second blow molds 910, 920after the stretching is performed.

Additionally, although embodiments are described above in which theupper and lower handle pocket wedge blocks 913, 925 are inserted intothe handle pocket 124 of the stretched preform 130 from opposite sides,the invention is not limited thereto. According to one or moreembodiments of the present invention, one of the first and second blowmolds 910, 920 may have a single handle pocket wedge block that takes upthe entirety of the handle pocket 124 to move and/or modify the integralhandle 123 by itself.

While the stretched preform 130 and formed container 150 shown in FIGS.7B and 7C are used as an example in FIGS. 4A-5B, a similar manufacturingprocess may be employed to form the preforms 210, 310, 410, 510, 610shown in FIGS. 8, 10, 12, 14, and 16, as well as other preforms.

FIG. 6 shows a cross-sectional view of a preform 110 according to one ormore embodiments of the present invention, and FIG. 7A shows a frontview of a preform 110 according to one or more embodiments of thepresent invention. In FIGS. 6 and 7A, the preform 110 is oriented withan open mouth portion 112 at the top. According to one or moreembodiments of the present invention, the preform 110 is formed fromplastic. The preform 110 has a threaded neck portion 111 at the top,with the open mouth portion 112 formed therein. The preform 110 furtherhas a main body 113 below the neck portion 111, a thick portion 117below the main body 113, and a semi-spherical end portion 119 formed atthe bottom of the preform 110. The preform 110 has a tapered transitionportion 115 formed between the main body 113 and the thick portion 117,such that the thickness of the preform increases gradually from the mainbody 113 to the thick portion 117. The inner surfaces of the neckportion 111, the main body 113, the transition portion 115, the thickportion 117, and the end portion 119 form a cavity 114 of the preform110. A base 121 of the cavity 114 is formed by the end portion 119.

According to one or more embodiments of the present invention, the neckportion 111, the main body 113, the transition portion 115, and thethick portion 117 have substantially the same diameter, while the outerdiameter of the thick portion 117 is greater than that of the main body113, with the transition portion 115 bridging the two outer diameters.According to one or more embodiments of the present invention, thethickness of the end portion 119 is the same as the thickness of themain body 113. The preform 110 also has a thread stop formed at thebottom of the neck portion 111. According to one or more embodiments ofthe present invention, an inner circumference of the end portion 119comprises a small ring-shaped notch for engagement with the stretch rod950.

According to one or more embodiments of the present invention, thepreform 110 is formed with an integral handle 123. The integral handle123 is attached to the main body 113 at an upper attachment point 125,and to the transition portion 115 at a lower attachment point 127.According to one or more embodiments of the present invention, the lowerattachment point 127 is disposed at a middle portion of the transitionportion 115. The integral handle 123 extends outwards from the upperattachment point 125, and curves downwards to a straight handle portion,then inwards towards the lower attachment point 127. A handle pocket 124is formed within the integral handle 123, bounded by the integral handle123, the main body 113, and a portion of the transition portion 115.

FIG. 7B shows a front view of a stretched preform 130 formed fromstretching the preform 110 shown in FIGS. 6 and 7A, according to one ormore embodiments of the present invention. The stretched preform 130 issimilar to the non-stretched preform 110 above the transition portion115 as well as the end portion 119 and, therefore, a description thereofis omitted. As shown in FIGS. 7A-7B, the transition portion 115 isstretched by the stretch rod 950 to form the upper thinned portion 131,while the thick portion 117 is stretched by the stretch rod 950 to formthe lower thinned portion 133. According to one or more embodiments ofthe present invention, the main body 113, the upper thinned portion 131,and the lower thinned portion 133 have substantially the same thickness.Alternatively, according to one or more embodiments of the presentinvention, the main body 113, the upper thinned portion 131, and thelower thinned portion 133 may vary in thickness, albeit to a lesserdegree than before stretching.

FIG. 7C shows a front view of a blown container 150 formed from blowingthe stretched preform 130 shown in FIG. 7B, according to one or moreembodiments of the present invention. According to one or moreembodiments of the present invention, a shape of the blown container 150corresponds to the shape of the first and second blow mold recesses 911,921 of the first and second blow molds 910, 920. As shown in FIGS.7B-7C, according to one or more embodiments of the present invention,when the stretched preform 130 is blown, positions of the first andsecond attachment points 125, 127 shift outwards, such that positions ofthe integral handle 123 and the handle pocket 124 shift whilesubstantially maintaining the original shapes thereof Alternatively,according to one or more embodiments of the present invention, a shapeand/or thickness of the integral handle 123 and a shape and/or size ofthe handle pocket 124 may be modified during the blowing process.

FIG. 8 shows a cross-sectional view of a preform 210 according to one ormore embodiments of the present invention, and FIG. 9A shows a frontview of a preform 210 according to one or more embodiments of thepresent invention. In FIGS. 8 and 9A, the preform 210 is oriented withan open mouth portion 212 at the top. According to one or moreembodiments of the present invention, the preform 210 is formed fromplastic. The preform 210 has a threaded neck portion 211 at the top,with the open mouth portion 212 formed therein. The preform 210 furtherhas a main body 213 below the neck portion 211, a thick portion 217below the main body 213, and a semi-spherical end portion 219 formed atthe bottom of the preform 210. The preform 210 has a tapered transitionportion 215 formed between the main body 213 and the thick portion 217,such that the thickness of the preform increases gradually from the mainbody 213 to the thick portion 217. The inner surfaces of the neckportion 211, the main body 213, the transition portion 215, the thickportion 217, and the end portion 219 form a cavity 214 of the preform210. A base 221 of the cavity 214 is formed by the end portion 219.

According to one or more embodiments of the present invention, the neckportion 211, the main body 213, the transition portion 215, and thethick portion 217 have substantially the same diameter, while the outerdiameter of thick portion 217 is greater than that of the main body 213,with the transition portion 215 bridging the two outer diameters.According to one or more embodiments of the present invention, thethickness of the end portion 219 is the same as the thickness of themain body 213. The preform 210 also has a thread stop formed at thebottom of the neck portion 211. According to one or more embodiments ofthe present invention, an inner circumference of the end portion 219comprises a small ring-shaped notch for engagement with the stretch rod950.

According to one or more embodiments of the present invention, thepreform 210 is formed with an integral handle 223. The integral handle223 is attached to the main body 213 at an upper attachment point 225,and to an uppermost portion of the thick portion 217 at a lowerattachment point 227, immediately below the transition portion 215. Theintegral handle 223 extends outwards from the upper attachment point225, and curves downwards to a straight handle portion, then inwardstowards the lower attachment point 227. A handle pocket 224 is formedwithin the integral handle 223, bounded by the integral handle 223 andthe main body 213 and a portion of the transition portion 215.

FIG. 9B shows a front view of a stretched preform 230 formed fromstretching the preform 210 shown in FIGS. 8 and 9A, according to one ormore embodiments of the present invention. The stretched preform 230 issimilar to the non-stretched preform 210 above the transition portion215 as well as the end portion 219 and, therefore, a description thereofis omitted. As shown in FIGS. 9A-9B, the transition portion 215 isstretched by the stretch rod 950 to form the upper thinned portion 231,while the thick portion 217 is stretched by the stretch rod 950 to formthe lower thinned portion 233. According to one or more embodiments ofthe present invention, the main body 213, the upper thinned portion 231,and the lower thinned portion 233 have substantially the same thickness.Alternatively, according to one or more embodiments of the presentinvention, the main body 213, the upper thinned portion 231, and thelower thinned portion 233 may vary in thickness, albeit to a lesserdegree than before stretching.

FIG. 9C shows a front view of a blown container 250 formed from blowingthe stretched preform 230 shown in FIG. 9B, according to one or moreembodiments of the present invention. According to one or moreembodiments of the present invention, a shape of the blown container 250corresponds to the shape of the first and second blow mold recesses 911,921 of the first and second blow molds 910, 920. As shown in FIGS.9B-9C, according to one or more embodiments of the present invention,when the stretched preform 230 is blown, positions of the first andsecond attachment points 225, 227 shift outwards, such that positions ofthe integral handle 223 and the handle pocket 224 shift, whilesubstantially maintaining the original shapes thereof. Alternatively,according to one or more embodiments of the present invention, a shapeand/or thickness of the integral handle 223 and a shape and/or size ofthe handle pocket 224 may be modified during the blowing process.

FIG. 10 shows a cross-sectional view of a preform 310 according to oneor more embodiments of the present invention, and FIG. 11A shows a frontview of a preform 310 according to one or more embodiments of thepresent invention. In FIGS. 10 and 11A, the preform 310 is oriented withan open mouth portion 312 at the top. According to one or moreembodiments of the present invention, the preform 310 is formed fromplastic. The preform 310 has a threaded neck portion 311 at the top,with the open mouth portion 312 formed therein. The preform 310 furtherhas a main body 313 below the neck portion 311, a thick portion 317below the main body 313, and a semi-spherical end portion 319 formed atthe bottom of the preform 310. The preform 310 has a tapered transitionportion 315 formed between the main body 313 and the thick portion 317,such that a thickness of the preform increases gradually from the mainbody 313 to the thick portion 317. The inner surfaces of the neckportion 311, the main body 313, the transition portion 315, the thickportion 317, and the end portion 319 form a cavity 314 of the preform310. A base 321 of the cavity 314 is formed by the end portion 319.

According to one or more embodiments of the present invention, the neckportion 311, the main body 313, the transition portion 315, and thethick portion 317 have substantially the same diameter, while the outerdiameter of thick portion 317 is greater than that of the main body 313,with the transition portion 315 bridging the two outer diameters.According to one or more embodiments of the present invention, thethickness of the end portion 319 is the same as the thickness of themain body 313. The preform 310 also has a thread stop formed at thebottom of the neck portion 311. According to one or more embodiments ofthe present invention, an inner circumference of the end portion 319comprises a small ring-shaped notch for engagement with the stretch rod950.

According to one or more embodiments of the present invention, thepreform 310 is formed with an integral handle 323. The integral handle323 is attached to the main body 313 at an upper attachment point 325and a lower attachment point 327. According to one or more embodimentsof the present invention, the lower attachment point 327 is immediatelyabove the transition portion 315. The integral handle 323 extendsoutwards from the upper attachment point 325, and curves downwards to astraight handle portion, then inwards towards the lower attachment point327. A handle pocket 324 is formed within the integral handle 323,bounded by the integral handle 323 and the main body 313 and a portionof the transition portion 315.

FIG. 11B shows a front view of a stretched preform 330 formed fromstretching the preform 310 shown in FIGS. 10 and 11A, according to oneor more embodiments of the present invention. The stretched preform 330is similar to the non-stretched preform 310 above the transition portion315 as well as the end portion 319 and, therefore, a description thereofis omitted. As shown in FIGS. 11A-11B, the transition portion 315 isstretched by the stretch rod 950 to form the upper thinned portion 331,while the thick portion 317 is stretched by the stretch rod 950 to formthe lower thinned portion 333. According to one or more embodiments ofthe present invention, the main body 313, the upper thinned portion 331,and the lower thinned portion 333 have substantially the same thickness.Alternatively, according to one or more embodiments of the presentinvention, the main body 313, the upper thinned portion 331, and thelower thinned portion 333 may vary in thickness, albeit to a lesserdegree than before stretching.

FIG. 11C shows a front view of a blown container 350 formed from blowingthe stretched preform 330 shown in FIG. 11B, according to one or moreembodiments of the present invention. According to one or moreembodiments of the present invention, a shape of the blown container 350corresponds to the shape of the first and second blow mold recesses 911,921 of the first and second blow molds 910, 920. As shown in FIGS.11B-11C, according to one or more embodiments of the present invention,when the stretched preform 330 is blown, positions of the first andsecond attachment points 325, 327 shift outwards, such that positions ofthe integral handle 323 and the handle pocket 324 shift, whilesubstantially maintaining the original shapes thereof. Alternatively,according to one or more embodiments of the present invention, a shapeand/or thickness of the integral handle 323 and a shape and/or size ofthe handle pocket 324 may be modified during the blowing process.

FIG. 12 shows a cross-sectional view of a preform 410 according to oneor more embodiments of the present invention, and FIG. 13A shows a frontview of a preform 410 according to one or more embodiments of thepresent invention. In FIGS. 12 and 13A, the preform 410 is oriented withan open mouth portion 412 at the top. According to one or moreembodiments of the present invention, the preform 410 is formed fromplastic. The preform 410 has a threaded neck portion 411 at the top,with the open mouth portion 412 formed therein. The preform 410 furtherhas a main body 413 below the neck portion 411, a thick portion 417below the main body 413, and a semi-spherical end portion 419 formed atthe bottom of the preform 410. The preform 410 has a tapered transitionportion 415 formed between the main body 413 and the thick portion 417,such that the thickness of the preform increases gradually from the mainbody 413 to the thick portion 417. The inner surfaces of the neckportion 411, the main body 413, the transition portion 415, the thickportion 417, and the end portion 419 form a cavity 414 of the preform410. A base 421 of the cavity 414 is formed by the end portion 419.

According to one or more embodiments of the present invention, a lowerportion of the main body 413, the transition portion 415, and the thickportion 417 have substantially the same diameter. An inner diameter ofthe neck portion 411 is larger than that of the lower portion of themain body 413, the transition portion 415, and the thick portion 417. Atapered inner diameter transition portion 428 is formed in the main body413 between the neck portion 411 and the remainder of the main body 413,bridging the two different diameters. While the tapered inner diametertransition portion 428 is formed at the top of the main body 413 inFIGS. 12-13A, the tapered inner diameter transition portion 428 couldalso be formed at other portions of the preform 410, as long as theinner diameter decreases or stays the same in the downward direction,such that the stretch rod 950, which may have correspondingly varieddiameters, can be inserted into and removed from the cavity 414.

The outer diameter of thick portion 417 is greater than that of the mainbody 413, with the transition portion 415 bridging the two outerdiameters. According to one or more embodiments of the presentinvention, the thickness of the end portion 419 is the same as thethickness of the main body 413. The preform 410 also has a thread stopformed at the bottom of the neck portion 411. According to one or moreembodiments of the present invention, an inner circumference of the endportion 419 comprises a small ring-shaped notch for engagement with thestretch rod 950.

According to one or more embodiments of the present invention, thepreform 410 is formed with an integral handle 423. The integral handle423 is attached to the main body 413 at an upper attachment point 425,and to the transition portion 415 at a lower attachment point 427.According to one or more embodiments of the present invention, the lowerattachment point 427 is disposed at a middle portion of the transitionportion 415. The integral handle 423 extends outwards from the upperattachment point 425, and curves downwards to a straight handle portion,then inwards towards the lower attachment point 427. A handle pocket 424is formed within the integral handle 423, bounded by the integral handle423 and the main body 413 and a portion of the transition portion 415.

FIG. 13B shows a front view of a stretched preform 430 formed fromstretching the preform 410 shown in FIGS. 12 and 13A, according to oneor more embodiments of the present invention. The stretched preform 430is similar to the non-stretched preform 410 above the transition portion415 as well as the end portion 419 and, therefore, a description thereofis omitted. As shown in FIGS. 13A-13B, the transition portion 415 isstretched by the stretch rod 950 to form the upper thinned portion 431,while the thick portion 417 is stretched by the stretch rod 950 to formthe lower thinned portion 433. According to one or more embodiments ofthe present invention, the main body 413, the upper thinned portion 431,and the lower thinned portion 433 have substantially the same thickness.Alternatively, according to one or more embodiments of the presentinvention, the main body 413, the upper thinned portion 431, and thelower thinned portion 433 may vary in thickness, albeit to a lesserdegree than before stretching.

FIG. 13C shows a front view of a blown container 450 formed from blowingthe stretched preform 430 shown in FIG. 13B, according to one or moreembodiments of the present invention. According to one or moreembodiments of the present invention, a shape of the blown container 450corresponds to the shape of the first and second blow mold recesses 911,921 of the first and second blow molds 910, 920. As shown in FIGS.13B-13C, according to one or more embodiments of the present invention,when the stretched preform 430 is blown, positions of the first andsecond attachment points 425, 427 shift outwards, such that positions ofthe integral handle 423 and the handle pocket 424 shift whilesubstantially maintaining the original shapes thereof. Alternatively,according to one or more embodiments of the present invention, a shapeand/or thickness of the integral handle 423 and a shape and/or size ofthe handle pocket 424 may be modified during the blowing process.

FIGS. 14 and 15A show cross-sectional views of a preform 510 accordingto one or more embodiments of the present invention. In FIGS. 14 and15A, the preform 510 is oriented with an open mouth portion 512 at thetop. According to one or more embodiments of the present invention, thepreform 510 is formed from plastic. The preform 510 has a threaded neckportion 511 at the top, with the open mouth portion 512 formed therein.The preform 510 further has a main body 513 below the neck portion 511,a thick portion 517 below the main body 513, and a semi-spherical endportion 519 formed at the bottom of the preform 510. The preform 510 hasa tapered transition portion 515 formed between the main body 513 andthe thick portion 517, such that a thickness of the preform increasesgradually from the main body 513 to the thick portion 517. The innersurfaces of the neck portion 511, the main body 513, the transitionportion 515, the thick portion 517, and the end portion 519 form acavity 514 of the preform 510. A base 521 of the cavity 514 is formed bythe end portion 519.

According to one or more embodiments of the present invention, the neckportion 511, the main body 513, the transition portion 515, and thethick portion 517 have substantially the same diameter, while the outerdiameter of thick portion 517 is greater than that of the main body 513,with the transition portion 515 bridging the two outer diameters.According to one or more embodiments of the present invention, thethickness of the end portion 519 is the same as the thickness of themain body 513. The preform 510 also has a thread stop formed at thebottom of the neck portion 511. According to one or more embodiments ofthe present invention, an inner circumference of the end portion 519comprises a small ring-shaped notch for engagement with the stretch rod950.

According to one or more embodiments of the present invention, thepreform 510 is formed with an upper handle attachment notch 525 and alower handle attachment notch 527. The upper handle attachment notch 525disposed on the main body 513, and the lower handle attachment notch 527is disposed on the transition portion 515. According to one or moreembodiments of the present invention, the lower handle attachment notch527 is disposed at a middle portion of the transition portion 515.Alternatively, the lower attachment notch 527 may be disposed on themain body 513 or the thick portion 517.

FIG. 15B shows a cross-sectional view of a stretched preform 530 foilled from stretching the preform 510 shown in FIGS. 14 and 15A, accordingto one or more embodiments of the present invention. The stretchedpreform 530 is similar to the non-stretched preform 510 above thetransition portion 515 as well as the end portion 519 and, therefore, adescription thereof is omitted. As shown in FIGS. 15A-15B, thetransition portion 515 is stretched by the stretch rod 950 to form theupper thinned portion 531, while the thick portion 517 is stretched bythe stretch rod 950 to form the lower thinned portion 533. According toone or more embodiments of the present invention, the main body 513, theupper thinned portion 531, and the lower thinned portion 533 havesubstantially the same thickness. Alternatively, according to one ormore embodiments of the present invention, the main body 513, the upperthinned portion 531, and the lower thinned portion 533 may vary inthickness, albeit to a lesser degree than before stretching.

FIG. 15C shows a front view of a blown container 550 formed from blowingthe stretched preform 530 shown in FIG. 15B, according to one or moreembodiments of the present invention. According to one or moreembodiments of the present invention, a shape of the blown container 550corresponds to the shape of the first and second blow mold recesses 911,921 of the first and second blow molds 910, 920, although wedge blocksand handle recesses would not be part of the blow molds 910, 920 for theblown container 550. As shown in FIGS. 15B-15C, according to one or moreembodiments of the present invention, when the stretched preform 530 isblown, the first and second handle attachment notches 525, 527 shiftoutwards. After the blown container 550 is formed, a handle may beattached to the handle attachment notches 525, 527.

FIGS. 16-17A show cross-sectional views of a preform 610 according toone or more embodiments of the present invention. In FIGS. 16-17A, thepreform 610 is oriented with an open mouth portion 612 at the top.According to one or more embodiments of the present invention, thepreform 610 is formed from plastic. The preform 610 has a threaded neckportion 611 at the top, with the open mouth portion 612 formed therein.The preform 610 further has an upper thick portion 623 below the neckportion, a main body 613 below the upper thick portion 623, a lowerthick portion 617 below the main body 613, and a semi-spherical endportion 619 formed at the bottom of the preform 610. The preform 610 hasan upper tapered transition portion 625 formed between the upper thickportion 623 and the main body 613, and a lower tapered transitionportion 615 formed between the main body 613 and the thick portion 617,such that a thickness of the preform increases gradually from the mainbody 613 to the upper and lower thick portions 617, 623, respectively.The inner surfaces of the neck portion 611, the main body 613, the upperand lower transition portions 625, 615, the upper and lower thickportions 623, 617, and the end portion 619 form a cavity 614 of thepreform 610. A base 621 of the cavity 614 is formed by the end portion619.

According to one or more embodiments of the present invention, the neckportion 611, the main body 613, the upper and lower transition portions625, 615, and the upper and lower thick portions 623, 617 havesubstantially the same diameter, while the outer diameter of the upperand lower thick portions 612, 617 are greater than that of the main body613, with the transition portion 615 bridging the outer diameters.According to one or more embodiments of the present invention, thethickness of the end portion 619 is the same as the thickness of themain body 613. The preform 610 also has a thread stop formed at thebottom of the neck portion 611. According to one or more embodiments ofthe present invention, an inner circumference of the end portion 619comprises a small ring-shaped notch for engagement with the stretch rod950.

FIG. 17B shows a cross-sectional view of a stretched preform 630 formedfrom stretching the preform 610 shown in FIGS. 16 and 17A, according toone or more embodiments of the present invention. As shown in FIGS.17A-17B, the upper and lower transition portions 625, 615 are stretchedby the stretch rod 950 to form the second and third thinned portions635, 631, while the upper and lower thick portions 623, 617 arestretched by the stretch rod 950 to form the first and fourth thinnedportions 633, 632. According to one or more embodiments of the presentinvention, the main body 613 and the first, second, third, and fourththinned portions 633, 635, 631, 632 may vary in thickness, albeit to alesser degree than before stretching.

FIG. 17C shows a front view of a blown container 650 formed from blowingthe stretched preform 630 shown in FIG. 17B, according to one or moreembodiments of the present invention. According to one or moreembodiments of the present invention, a shape of the blown container 650corresponds to the shape of the first and second blow mold recesses 911,921 of the first and second blow molds 910, 920 although wedge blocksand handle recesses would not be part of the blow molds 910, 920 for theblown container 650. Varying the thicknesses of across the stretchedpreform 630 allows for greater degrees of freedom in shapes of the finalblown container 650.

While the disclosure has been presented with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments may be devised whichdo not depart from the scope of the present disclosure. Accordingly, thescope of the invention should be limited only by the attached claims.

What is claimed is:
 1. A preform for a container, comprising: a hollowcylindrical main body having a first thickness; a hollow cylindricalthick portion having a second thickness greater than the firstthickness; and a curved end portion, wherein inner surfaces of the mainbody, the thick portion, and the end portion form a cavity.
 2. Thepreform as recited in claim 1, wherein an outer diameter of the thickportion is greater than that of the main portion.
 3. The preform asrecited in claim 1, wherein an inner diameter of the thick portion isthe same as that of the main portion.
 4. The preform as recited in claim1, further comprising: a tapered transition portion formed between themain body and the thick portion, such that the thickness increasesgradually from the main body to the thick portion.
 5. The preform asrecited in claim 2, further comprising: a tapered transition portionformed between the main body and the thick portion, such that the outerdiameter increases gradually from the main body to the thick portion. 6.The preform as recited in claim 1, further comprising: a threaded neckportion disposed above the main body.
 7. The preform as recited in claim1, further comprising: an integral handle attached to the main body atan upper attachment point, and attached to the thick portion at a lowerattachment point.
 8. The preform as recited in claim 1, furthercomprising: an integral handle attached to the main body at both anupper attachment point and a lower attachment point.
 9. The preform asrecited in claim 4, further comprising: an integral handle attached tothe main body at an upper attachment point, and attached to the taperedtransition portion at a lower attachment point.
 10. The preform asrecited in claim 5, further comprising: an integral handle attached tothe main body at an upper attachment point, and attached to the taperedtransition portion at a lower attachment point.
 11. The preform asrecited in claim 1, wherein the main body comprises a tapered innerdiameter transition portion that gradually decreases an inner diameterof the main body in the downward direction.
 12. The preform as recitedin claim 4, further comprising: an upper handle attachment notchdisposed on the main body, and a lower handle attachment notch disposedon the tapered transition portion.
 13. The preform as recited in claim5, further comprising: an upper handle attachment notch disposed on themain body, and a lower handle attachment notch disposed on the taperedtransition portion.
 14. The preform as recited in claim 1, furthercomprising: another thick portion disposed on an upper side of the mainbody and having a third thickness greater than the first thickness,wherein the thick portion is disposed on a lower side of the main body.15. A mold for forming a preform, comprising: a first preform moldcomprising a first preform mold cavity that includes a first top openingand a first bottom opening; a second preform mold comprising a secondpreform mold cavity that includes a second top opening and a secondbottom opening; a third preform mold comprising a third preform moldcavity that includes a third top opening, and a third bottom opening;and a rod-shaped inner mold, wherein the first preform mold and thesecond preform mold are configured to be combined such that the firstand second preform mold cavities form a first space corresponding to anouter shape of an upper portion of the preform having a variable outerdiameter, wherein the third preform mold cavity has a second spacecorresponding to an outer shape of a lower portion of the preform havinga constant outer diameter, wherein the rod-shaped inner mold isconfigured to be inserted into the first, second, and third preform moldcavities and corresponds to an inner cavity of the preform, and whereinthe third preform mold is structured such that molten plastic can beinjected through the third bottom opening.
 16. The mold for forming thepreform as recited in claim 15, wherein, when the first, second, andthird preform molds are combined, the first and second bottom openingsof the first and second preform mold cavities communicate with the thirdtop opening of the third preform mold cavity, such that molten plasticinjected from the third bottom opening can flow to the first and secondpreform mold cavities.
 17. The mold for forming the preform as recitedin claim 15, wherein the first and second mold cavities compriserecesses in the shape of a handle.
 18. A method for forming a preform,comprising: closing a first preform mold comprising a first preform moldcavity that includes a first top opening and a first bottom opening, asecond preform mold comprising a second preform mold cavity thatincludes a second top opening and a second bottom opening, such that thefirst and second preform mold cavities form a first space correspondingto an outer shape of an upper portion of the preform having a variableouter diameter; disposing a third preform mold comprising a thirdpreform mold cavity that includes a third top opening, and a thirdbottom opening below the closed first and second preform molds, thethird preform mold cavity having a second space corresponding to anouter shape of a lower portion of the preform having a constant outerdiameter; inserting a rod-shaped inner mold into the first, second, andthird preform mold cavities, injecting molten plastic through the thirdbottom opening into the first, second, and third preform mold cavities,and around an outside of the rod-shaped inner mold; cooling the moltenplastic to form a hardened plastic preform; removing the first, second,and third preform molds to expose an outside of the preform; andremoving the rod-shaped inner mold from the preform.
 19. The method forforming the preform as recited in claim 18, wherein the first and secondmold cavities comprise recesses in the shape of a handle.
 20. The methodfor forming the preform as recited in claim 18, wherein at least aportion of the inner diameter of the closed first and second preformmold cavities is greater than an inner diameter of the third preformmold cavity.